Take a walking tour of San Francisco's best and famous chocolate eateries. Either do your own self-tour or take one by www.gourmetwalks.com. These tours are at 10:30am Wednesdays and Fridays and 2pm Saturdays.
For your own walking tour:
Scharffenberger Chocolate Maker - Ferry Building Marketplace, One Ferry Building, Shop #14. 415-981-9150. Better yet, drive to Berkeley to visit their headquarters.